Market researchers Mintel found that four out of five families have changed their food shopping habits because of recent price rises and the general squeeze on living standards.

One in three households now buys less food. Top of the list of cut backs were fruit and vegetables and organic meat.

While the big four supermarkets (Tesco, Asda, Sainsbury's and Morrisons) claim they are offering promotions to lessen the impact of price rises, a survey complied for the Daily Mail by the shopping site mySupermarket found huge price rises on staple products, including own-label brands.

For example, Sainsbury's own-brand corn flakes have gone up by 37 per cent while its iceberg lettuce now costs 18 per cent more than it did this time last year.

Research also found that Tesco's own-label butter had gone up by 25 per while the cost of cauliflower was up by 15 per cent.

James Foord, of mySupermarket, said: "In the past year alone, shoppers have been subject to double-digit price hikes to the contents of their shopping trolley.

"It is imperative consumers shop around for the best deals. Savvy shoppers can switch to cheaper budget products and supermarket own labels to make their budgets stretch."

A survey by consumer group Which? found that 84 per cent of shoppers are seriously worried about rising food costs and 39 per cent have started shopping at discount supermarkets such as Aldi and Llidl.